Sprocket shield



Feb. 14, 1939.

SPROCKET SHIELD D. B. BAKER ET AL 2,146,882

- Filed Aug. 13, 1937 spoke type, and it will be appreciated that rocks, thereof with the track frame, the edges of the 1f Patented Feb. 14, 1939 UNITED j STATES PATENT, OFFIQE SPRO CKET SHIELD David B. Baker, Riverside, Clifford R. Rogers, Oak Park, and William 0, Bechman, Chicago, Ill., assignors to International Harvester Company, a corporaticn of New Jersey Application August 13, 1937, Serial No. 158,888

4 Claims. (01. 305-8) This invention relates to a sprocket wheel of such a shape that it will deflect rock, stones, shield for a tractor of the crawler type. or the like, away from the sprocket wheel.

In the operation of crawler tractors over sandy Another important object is to provide the or rock-strewn terrain, it is important that cershield of such construction that it provides a 5 tain parts of the tractor be protected against comparatively tight fit with the sprocket wheel the entrance of rocks and the like. A point on and the track frame for the purpose of preventthe tractor that is particularly susceptible to the ing the entrance of fine or sandy soil. I

entrance of such foreign substances is the drive Another object is to mount the shield on the sprocket wheel. Most sprocket wheels are of the tractor frame in a manner permitting movement stones or the like, entering between the spokes shield adjacent the sprocket wheel remaining of the sprocket wheel and the tractor body, may constantly concentric therewith at all times.

cause considerable damage to component parts Another object is to provide means on the thereof. Most tractors of recent design genershield for securing the same to the track frame. ally comprise a main body portion having a shaft Another object is to provide attachment means 15 I extending from opposite sides thereof, on each on the shield for securing the same to the bearing extended end of which is carried a drive sprocket member. wheel. A track frame is disposed alongside each Still another object is to provide the shield sprocket wheel, being supported on the shaft by of sheet metal and to shap the same 8 as to a bearing means. The track frames are thereby enclose the bearing means and the spaces be- 50 pivotally mounted for vertical movement about tween the spokes of the sprocket wheels. the shaft and carry at their forward ends idler Briefly, these and other desirable objects are wheels about which are trained the endless track achieved in the instance of the present disbelts driven by the sprocket wheels. With this closure by p ov d a Shield Substantially in 5 construction, the track frames are usually disthe Shape Of a truncated Co e wherein the trunposed below the sprocket shaft and are provided cated surface is secured to the bearing means and with lower shield members, which successfully the edge comprising the base of the cone lies adprotect substantially the lower halves of the j t he plane of the sprocket wheel. This sprocket wheels. However, tractors of the crawlconical surface s provided w t integral ear porer type frequently op t in localities Where t tions for securing the shield to the track frame. soil is of such texture that the tractor for the In this manner, the e d s mounted for movemost of the time operates in soil to a depth well ment With the trach me a d remains conup to or over the sprocket shaft. At these times, stantly concentric Wlth e p oc et wheel durof course, it is desirable to provide additional 3 Vertical pivotal mqvement 0f the track frame.

5 shielding for protecting the upper portion of the A further understanding of the O j and sprocket wheel from the entrance of foreign subvantages of the invention y be had from the stances 1; i l necessary t t, shiem be following specification taken in conjunction with provided of such construction that a comparatheficcomptmylng Sheet of aw ngs, wherein: tively tight seal is provided by the sprocket wheel F1gu re 1 a general perspectlve ew, showing 40 and related supporting members, in as much as the shield in place on the track frame and its 40 both fine and coarse soils are found during difrela'mon to the Sprocket Wheel? Figure 2 is an enlarged end view partially in ferent operatmg conditions. It is also des1rable Section, Showing the relation of the inner edge v to provide a Shleld shaped to enclose the track of the shield to the sprocket wheel and showing frame bearing means to prevent the entrance also the means for securing the shield to the 45 of dirt thereto. Generally, it is of prime imbearing means; and

portance to provide Shield @fiording ample Figure 3 is a plan elevational view of the shield tection 1n the form of a dirt-free seal for all Shown on a somewhat reduced scam related parts wherein the entrance of foreign only Sumcient portions of the tractor and and indurate substances w ll contribute to the sprocket Wheel have been Shown as is} deemed 50 Wear and depreclatlon of Sald partsnecessary to illustrate the invention. The nu- The p l pal object O the invention, then, 15 meral It) indicates generally the main body porto provide a shield for a sprocket wheel of a ti of t t t i in t present tractor of the crawler type. stance, houses final drive gearing, not shown, for

An important object is to provide thisshield driving adrive sprocket wheel II. A transverse 55 spokes l3, which extendoutwardly to a sprocket wheel rim M. An endless track belt 15 is carried by the sprocket wheel II and extends forwardly;

alongside the tractor, being trained about ,a ,front idler wheel, not shown. A track frame member I6 is disposed alongside thesprocket'wheell Land extends forwardly alongside: the tractor and sup ports the front idler wheel, all-of whicliis-more or less conventional construction. In the presentcase, bearing means are provided for;supporting;

the track frame I6 on the outer end of the transverse shaft I2. This bearing means comprises a bracket memberv secured to the. track frame.

A ball andsocketjointis provided,.as at=- I8, and

cooperateswiththe bracket member, [51 foppivotally, mounting the -track. frame 16-. for verticalmovement aboutthershaft l2. This-mountingallows oscillation of the track frames as the tractor operates, over uneven terrain. The, surfaces.- between the component. parts-10f. the ball and.socket joint; I8.and.- the bracket, member l1 ar e-lubricated.to provide ease of movement of the track frame, andzthus itis important that entrancev thereto offine or; sandy-spit besprevented.

It,willr be; understood that; in. as; much, as, the

sprocket wheel It is of thespoke type, spaces will 1 be provided between the spokes, ,7 into which rocks, stones and the like may enter. As previously mentioned, ,it-is desirable to'hlcVentthe entrance of. such material. to both. the bearing; means and the sprocket wheel. To this end; a. shield I9: issecured to-thetrackframe; This shield ispreferably; formed of sheet; metal; and is: cupped orshaped; as; a; major; portion of; a; truncated: cone. The;- truncating; surface; or;-i1at' portion, 20 issecured to the bearingmeans by means. of bolts, 2| and spacer-sleeves 22:. The

sleeves 22. arepreferably secured toithe portion lll as by welding, toprovidefon convenient attachment of: the shield l9-to the trackframe: and bearing means.-

'Ilhecenical portion, or annularly. inclined 'portion, .is formed integral with; the portion'f20 and: extends inwardly. toward the sprocket wheel; as-at 23-, whereat the substantially; circular edge oom.-. prising the base of the cone lies adjacent the plane of the sprocket wheel; as' at 24. This circularedge is preferably/fitted Within the: rim I 4' of the sprocket wheel to providea; substantially. dirt-free seal therewith, A lower; edge of the portion 20 issubstantially straight, as g at: 25; and abuts or is otherwise associatedwith the track frame 16 ina manner providingg-a substantially dirt-free-seal:therewith. The lowenportions oftheqannularly inclined, or conical portion. 22 are formed straight, as at 26,, substantially in. alignment with the straight edgeJZSi: Means; inthe" form of-v earportions 21'; are secured by; bolts. 28 to the upper flange?ofrthetrackirame I6. These ears are preferably ormed on the shieldzby being bent. out from: the conical portion 22-; It-willzbe flat portion 20 is recessed.- in thevicinity of the bolts-2i; thus providing. a. flat. surface freerfn'om,

projections. It is also important that the heads of the bolts 2! be disposed inwardly of the flat portion 20 since they may be damaged during operation of the tractor.

From the foregoing description it will be apparent that a. suitable shield has been provided for affording ample protection against the entrance of foreign'substancesto the bearing means and'the sprocket wheel. It'will be noted that the relation between the substantially circular edge moi the shield and the rim [4 of the sprocket wheel; renders it virtually impossible for such foreign substances to gain entrance to any large extent. Similarly, the-provision of the edges 25 and 26gas cooperating with the track frame l6, also-,prevents theentrance of foreign substances. At'the same time, the practical value of the shield is,furtherenhanced bmthe shape thereof, which adds to the attractiveness of the tractor as a whole.

twwr r nde st of o e. th t nu erou modifications and, alterations. maxbe made; in

eah ve n uct o u h: the; hap of ehield nd e' m a s r. att hina am e. ck r m ndw ea i a-m ansi wit out.

e r in r m. hen iri nd scope 1 o he nnt n 1 s; efined n.- h pe d d 1 laima' h t is imeda s 1. A.wl' eel;shieldfor acrawler tractor having a hce ar iedv nwerd n of e'end; of. a. shaft; i

a: bearingmarriedat the end of. the shaft; outside a' el. nd: as ckz rame.car i dlbyxthe bearing and,2disposed horizontally-forwardlyand rear:- wa-rdlyof; the;bearing below -the: axis of the shaft a h ld; bein umed: off sheet metal: and ha d: a a melon co t ca o a truncated conecoaxial with the; Shaft; the shield beingv disposed a o e he rack rameand EDC I ebearing.

and that portion; of; the; wheel: disposed above the; traclc frame, its-s conical surface; extending.

of theconebeing;closedby-a portion of: the shield;

enclosing; and secured, to the bearing.

2. A wheel shieldfora crawler-tractor having a-w-heel carriedginwardly of the'endzof 'a shaft, a bearing carried'at; the end; of the shaft and-in.-

cluding a-portion lying inwardly. of; said end, and

a. trackframe, carried, by the bearing.- anddis.-

posed horizontally forwardly..- and rearwardly of; the bearingrbelow theaxisof. theishaft, said shield being; formed-' of. sheet metalx and; shaped as. a

major portionof: a. truncated conecoaxial; with 6 the, shaft, the shield being-- disposed abovethe track frame and, enclosing the bearing and that portion, of thewheel; disposed, above the track frame, its, conical surface. extending fromv the mar ian. of he frame. i a ward r 0f. e r tothat IQDIZ iQn, forwardly thereof, the edge com-.-

prisin th a e.- f. e. cone. g. osely. adia entthe wheel he rrncatedror io ha e.

in os d. by an. nte r oute crtiqnt f... heie i y n u stant ally, aral w h. the whe l and enclosing the bearing. and, the end, of, the,

shaft, spacing means interposed between this outer portion and; that portionof the bearing l n inwa ly he. s t. and. ans. or Se curing theshield to the bearing, V

3. A wheel shield fora crawler tractor having a wheel' carriedinwardly of the end of a shaft, a bearing carried at the end of; the shaft and including a portion lying inwardly OfSEtld end, and a track frame carried by the bearing and dis- Col posed horizontally forwardly and rearwardly of the bearing below the axis of the shaft, said shield being formed of sheet metal and shaped as a major portion of a truncated cone coaxial with the shaft, the shield being disposed above the track frame and enclosing the bearing and that portion of the wheel disposed above the track frame, its conical surface extending from the portion of the frame rearwardly of the bearing to that portion forwardly thereof, the edge comprising the base of the cone lying closely adjacent the Wheel, the truncated portion of the cone being closed by an integral outer portion of the shield lying substantially parallel with the wheel and enclosing the bearing and the end of the shaft, spacing means interposed between this outer portion and that portion of the bearing lying inwardly of the shaft, this outer portion of the shield being formed with inwardly extending recesses, and means for securing the shield to the bearing, said means passing through said outer portion and having their outer extremities disposed within the recesses to lie within the plane of the outer portion of the shield.

4. A wheel shield for a crawler tractor having a wheel carried inwardly of the end of a shaft, a bearing carried at the end of the shaft and including a portion lying inwardly of said end, and a track frame carried by the bearing and disposed horizontally forwardly and rearwardly of the bearing below the axis of the shaft, said shield being formed of sheet metal and shaped as a major portion of a truncated cone coaxial with the shaft, the shield being disposed above the track frame and enclosing the bearing and that porion of the wheel disposed above the track frame, its conical surface extending from the portion of the frame rearwardly of the bearing to that portion forwardly thereof, the shield at said portions being secured to the track frame, the edge comprising the base of the cone lying closely adjacent the wheel, the truncated portion of the cone being enclosed by an integral outer portion of the shield lying substantially parallel with the wheel and enclosing the bearing and the end of the shaft, a spacing sleeve interposed between this outer portion and that portion of the bearing lying inwardly of the shaft, said sleeve being arranged at right angles to the outer portion of the shield, said outer portion being formed with an inwardly extending recess substantially in alinement with said sleeve, the outer portion having an opening within the recess, and a bolt passing inwardly through said opening and cooperating with the bearing for securing the shield thereto, the head of the bolt lying within the recess.

DAVID B. BAKER. CLIFFORD R. ROGERS. WILLIAM O. BECHMAN. 

